1. Field of the Invention
The present invention relates to systems and methods for directing air flow through an electronics cabinet.
2. Description of the Related Art
Computer systems, along with other components that support their use and maintenance, generate large amounts of heat. This heat must be continually removed to prevent the components from reaching elevated temperatures that can cause damage or failure of the components. While heat sinks may be utilized to conduct heat away from a point source of heat and distribute that heat over a large surface area, it is air convection that is ultimately responsible for removing heat energy from the cabinet. In nearly all significant computer installations, the amount of heat that must be removed requires the use of forced convection through or around the heat producing component. The cabinets, chassis and individual components are designed and configured to accommodate the forced flow of air through channels in or between the components and remove sufficient heat to prevent damage to the components. Often, the air flow impedance of each device must be strictly controlled in order to maintain the proper internal distribution of airflow.
However, there are also limitations in how these components can be designed. For example, the components require electrical connections, computer cabling, visual indicators, maintenance accessibility, and structural integrity, as well as channels for air flow. Therefore, decisions about the amount and direction of air flow have to be made during the component design process in order to accommodate all of the foregoing objectives. Computer installations must then follow the fixed operational requirements that are dictated by the component design.
Furthermore, a modular chassis, such as a blade server, contains slots for the installation of subsystem devices or components. Each installable device is designed according to a specific chassis slot architecture which defines the power, cooling and mechanical support that the slot provides for the device, the electrical or optical signals between the chassis slot and the device, and, in the case of an input/output device, the external surface of the device so that input/output connectors, indicators, and controls will be accessible to the user of the chassis. In general, a device must be uniquely redesigned for each chassis slot into which it might be installed.
Among these design considerations, there are two main airflow orientations used within devices that are designed for use in a modular chassis. Orthogonal airflow, which includes side-to-side, top-to-bottom, and bottom-to-top airflow, allows the external surface of the device to be consumed with input/output connectors, indicators and displays, or input controls, without any need to provide surface area for airflow. Normal airflow, which includes front-to-back and back-to-front airflow, requires that the external surface of the device contain any input/output connects, outputs or inputs, along with the necessary air openings to provide the required air entry or exit.
Airflow orientation is a major constraining element in the design of these chassis and the devices that are installed into them. The airflow orientation in the chassis is chosen and designed to best accommodate the types of devices which will be installed in the architected slots. Devices are not interchangeable or inoperable between slots with different airflow orientations. A device designed specifically for airflow to enter or exit the chassis through its external surface, such as a normal airflow device using a perforated faceplate or bulkhead for air entry or exit, must be redesigned to operate in a slot having both air entry and exit provided through the chassis with no external airflow required or allowed, such as an orthogonal airflow device. In an orthogonal airflow device, the air enters at one or more locations around the device from within the chassis and exits from one or more distinct locations around the device back into the chassis. An orthogonal airflow device has a solid bulkhead and faceplate and provides no openings for airflow into or out of the chassis. Generally, an orthogonal airflow device can provide significantly more input/output density than a similarly sized normal airflow device, since no external surface space is reserved for airflow. However, normal airflow can be beneficial for an input/output device having external interface components that require airflow for cooling, such as input/output connectors that contain optical transceivers.
While some devices can be operated with airflow in either direction along a specific orientation, these devices are still not operable with airflow that is oriented at a right angle to the specified airflow. For example, an orthogonal airflow device can not be used in a chassis that provides only normal airflow. Some other devices are architected to operate in either of two positions as long as the airflow direction is reversed exactly 180 degrees. For example, certain components are compatible with either top-to-bottom or bottom-to-top airflow, based on which slot it is installed in. However, even these modules cannot operate in a slot where the airflow is from front-to-back.
Therefore, there is a need for an apparatus that would allow for the use of existing devices or components designed for one chassis slot architecture in different and incompatible chassis slot architecture. It would be desirable if this apparatus would allow a devices requiring orthogonal airflow to be used in a chassis providing normal airflow. It would be beneficial for the apparatus to be compact, yet provide sufficient airflow for cooling to prevent damage to the orthogonal airflow components.